Did you read here?
https://www.reddit.com/r/CoinBase/Many users have the same problem as me. However, unlike them, I have not received any email about closing the account. We have in common that we cannot withdraw in any way.
I am getting this error upon checking their sub-reddit.
upstream connect error or disconnect/reset before headers. reset reason: overflow
It seems that you're not alone posting these complains and everyone is having their share with what they're experiencing for their withdrawals. Well, this problem usually is being done by exchanges and if they're telling you that they will settle it within 5-7 days, more or less, nothing can be done but to wait.